Combination hydraulic and mechanical brake



Nov. l1, 1958 M. A. rHRoNE E'rAl. 25859339 COMBINATION HYDRAULIC AND MECHANICAL BRAKE Filed Dec. 21, 1953 4 Sheets-Sheet 1 Their Attorney Nov. ll, 1958 M. A THRoNx-z :TAL 2,859,839

COIIBINATION HYDRAULIC AND MECHANICAL BRAKE Filed nec. 21. 195s 4 Sheets-Sheet 2 Fig? Their Attorney Nov. 1l, 1958 M. A. THQNE Erm. 2,859,839

counumou mmmuuc mn uEcmmIcAL am Filed nec. 21, 195s 4 sheets-sheet s Fig. 3

INVENTOR. Maurice A. Thorne BY Lof/:rop M. Forbusb Th'r Attorney Nov. 1l, 1958 M. A` 'rl-lRoNE E11-AL y COMBINATION HYDRAULIC AND MECHANICAL BRAKE 4 Sheets-Sheet 4 Fund neo. 21,1953

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s Y 4 mm m. wrm "Il". "l IAM. m my n m 2 m0 m United States 2,859,839 cor/iBnvAH'otN'rrYnRAULIC 'AND1 MECHANICAL ABRAKE i Maurice A; Thorne,-Det1oit,' and; Lothrop /Mi -Forbush,

Ferndale, Micha assignors to General Motors Corporation, DetroitgrMich., a corporation of Deiaware Application Decernh'erZL11953,Serial?15163995524 i s errants..v {Cities-7st* This invention relates to a brake structure adapted for usezon motor vehicles.

An =object of the'invention is to "provide=an' improved hydraulically actuated brakefstructure that 'will :operate consistentlyy more uniformly under-varying `operating conditionsvand to incorporatey in ysuch a brakevstructure supplementarymechanical actuation of the` structure rectionofthe arrow 4 on-Figure 2.

Figure 5-is -a transverse cross sectional-view of'a'poratene() wherein.bothethevthydraulic.and-the mechanical actuation tion of the brakefrnechanism astakensubstantiallyalong Figure 6 is naftransverse cross sectional-view'ofanportionzofthe-brakemechanism-as taken substantiallyfalong line 6-'6 ofFigure 1.

Figure 7 is a transverse crosssectional-view cfa part-of lthe brake lmechanismrftaken along'line :f7-7 ofFigure 1. Thebrakernechanism -of-this invention is constructed asa .totally enclosedmechanismftoreduce toa minimum variable `brakeactionresulting -frorn changingl conditions of. operation Yof.a--rnotor vehicle on which thebr-ake is carried, such changing-conditions resultingfromvariable road :conditions over whichrthe vehicle travels;`

In; this inventionthe--fbrake structure fisfan integral part-,ofthe wheel structure and is -disposed relative to the-.fwheelustructureso asta-beV instal-ledfrom'the outboardidev of thewheel'. t v

The brake includesvboth 1. a: hydraulic actuating mech- ,anisrnforcontrolling brakesactiontas well as -anl-auxiliary mechanical actuating mechanism tha-t1 operates p onthe .samea brake t-shoes as-sare-7under control ofl'thehydranlic actuating vmechanismt` t The. `mechanical --actua-tingf tmech anisrnmfor theztbrake-Aextends. through the wheel' `axle=on on the in-board endofthe wheelfaxle. The brake 'mechanism. offthis invention is carriedl fully onthe'wheelaXle in a manneras Willfeliminate the necessity of the-use of back plates `asfrequired in .conventional brake` mech- .mounted,thernechanical ractuating-device beingjcarried anisms. Ths, the wheel as well -as-sthe. brake mechanism 11 Patented Nov. 11, 1958 Mice 2 is carried =on the axle asan independentstructure,` thel wheel and thefbrake drum' being so associated as to providel a `total enclosure for the lbrake mechanismtoreduce' to: a zminimum =thel adverse effects of varying` weather xeon ditions onthe brake mechanism.

Irr'the drawingsiv` the wheel andv brake mechanism is illustrated vvfor'useas thefrontwheel of a niotorvehicle:4v

The motor vehicle-'has `a spindle or aXle 210 extending horizontally relative tothe kingpin `bearingsfllz-and :12 that receive la kingpin 13"journaled s therein:V Thefaxle spindle-10 has lan axiall opening 14Y extending. tliro'ugh` the spindle Ml; the axial-openingft14 receiving -the mechanical actuating mechanism-` `tfor: `thel brake structurey asherein'- after described;

The axle spindle 10'has an inboard vanti.-friction'bearing 15- carried adjacent the-i kingpin: 13.* Thet bearing 115 -ncludes an? inner ball race 16 'journaled-on the-'outer periphery T17vv of the-axlefspindle 10: An outerball race 18 isfcarriedin-.one end ofthe hubx19g' the hub` 19 bein'g integral withl the wheel llange 20 thatforms onefenclosing Wall for `the brake structure laslhereinafter described:

The'bearingIES-isclosed by an oilrs'eal-Zlthatinturn is protected by a sheet frnetal ycover v22 enclosingA the inboa-rden dfof vthe hub I19i as positioned; between theinne'r race ,-162 of the bearingY :154 andthel shoulder: 23Y yprovided on the laxle'spiridlel: i

Asecondfanti-frictionbearing25fis providedatv1 the outboard end 26 of the hub 19v between thehb anda the periphery '17 of--they axle-spindlefvltkv` Thisf 'out-board bearing 25-inclu`des an i inner ball. race 27" joural'edfon the peripheral surface"17 of-'the'spiiidle10and1'anfouter ball=racey23 thatfis carried in the 'out-'board end 26V`of the hub- 19:- vAn` oil'seali29fis 'providedy between? thcfiniie'r recessthat carries thev outerballraceE '2812-' Y Theouter-ball racexlS of the Ybearing 15"-is carried inthe axial recess 31 in the hub 19 and engages a radialiian'g'e 312.m Likewise; the `outer ball tra'ce- 285 carried i'nVJ the axial `recess 3tlengagesa radial llang'e 33vin the hubf19;

kinsure accurateconcentric positioning.;`v of the brakeldrurn 45-relative-to the axis of the wheel.`

The brake drum 45 is a composite structureincluding a formed metal shell 46 that includes a transverse wall 47 fully-closingone end of the brake' drum. An-annnlar reinforcing ring mais bonded to the inner periphery! of the -annular -wall of thee-formed shell 46 whereby toprvide a relatively'stilAV drum-lwall thatis `engaged'bythe -braketshoes of the brake'` structure; l -Thebrake drum45-is 'carriedon:thefradialiflangeiiSU that extendsfrom the wheel'iiangeZll as anintegral part thereof, fasteningstuds'51 being securedin suitableopenings-52 in, the ange 50;

The fastening studs 51'include a` threadedportion-SS `that receives a retaining nut` 54- whicl-r engages a` tapered opening SS provided in theV radial flange'on the brake drum 45. Asillustrated in Figure 1 the angesS-of' the brake-drum'45 is a multi-sidedl flangemember` providing Vthereby substantially triangular shaped 'an'gerareas 56a to 56j inclusive eachof Vwhichreceives one of theretaining nuts 54 whereby tov hold the brake :drumi45' upon radial "flangeSQ .of fthe' `wheel lange- 20?' A wheel rim 60 is provided with an inwardly turned radial flange 61 secured to the rim 60 by a plurality of rivets 62. The wheel flange 61 has an internal periphery substantially matching the periphery of the ange 56 of the brake drum 45, as indicated in Figure 1, thus providing a plurality of arcuate areas 64a to 641 inclusive each of which has a tapered opening 65 that receives a fastening nut 66 that threadedly engages a fastening stud 67 mounted in the radial flange 50 of the wheel flange 20. Thus, the hexagonal shape of the flange 50 combined with the hexagonal interior of the wheel flange 61 makes it possible to provide the fastening device for the brake drum 45 and the wheel rim 60 on the same diameter from the axis of the wheel. This arrangement makes it possible to utilize a smaller diameter wheel rim or within a Wheel of a given size to increase the diameter of the brake drum to give greater friction area for engagement by the brake shoes within a given wheel diameter.

The brake structure incorporated within the brake drum 45 includes a wheel cylinder 70 having a cylinder bore 71 that receives a pair of oppositely acting wheel cylinder pistons 72. The wheel cylinder 70 is carried upon the upper end of a supporting arm 73 that engages the forward face 74 of the Wheel spindle 10. The forward face 74 of the wheel spindle 10 has radial splines or serrations 75 that engage corresponding and cooperating serrations or splines on the rear vface 76 of the supporting -arm 73. The cooperating splines or serrations prevent rotation of the wheel cylinder 70 relative to the wheel spindle 10.

The supporting arm 73 is secured to the wheel spindle by a plurality of bolts 77.

A brake shoe supporting arm 80 engages the forward face 190 of the supporting arm 73 and is carried thereon and secured thereto by the bolts 77a, 77b, and 77C. The brake shoe supporting arm 80 has enlarged end portions 81 and 82 the upper ends of which are formed normal to the plane of the arm 80 to provide supporting legs 83 and 84. Corresponding supporting legs 85 and 86 are provided at the bottom ends of the brake shoe supporting arm 80.

A brake shoe 90 having the radial web 91 is carried upon the supporting legs 83 and 85 of the member 80, the radial face of the web 91 engaging the supporting legs 83 and 85 to maintain the periphery of the brake shoe coaxial with the axis of the wheel and of the brake drum 45. The web 91 of the brake shoe 90 is retained yagainst the supporting legs 83, 85 by a resilient connection 95 illustrated in Figure 7 comprising the pin 94 and a spring 96.

Similarly, the brake shoe 100 has the radial web 101 carried upon the supporting legs 84 and 86 to position the brake shoe 100 coaxial with the brake drum 45. The brake shoe 100 is held against the supporting legs 84 and 86 by a resilient connection 95a of the same kind as that illustrated in Figure 7.

The upper ends 102 and 103 of the brake shoes 90 and 100 respectively engage opposite sides of an anchor pin 104 that is secured within a protrusion 105 extending upwardly from the brake cylinder 70. The protrusion 105 has a slot 106 that receives the ends 102 and 103 of the brake shoes 90 and 100 whereby the upper ends of the brake shoes are retained in controlled position relative to an axial position in respect to the brake drum 45.

Retraction springs 107 and 10S have one end of each of the springs engaging the protrusion 109 on the anchor pin 104, the opposite ends of the springs 107 and 108 'being carried in the holes 110 and 111 in the brake shoe webs 91 and 101 respectively.

The opposite ends 112 and 113 of the brake shoes 90 and 100 respectively engage opposite ends of an adjusting device 115 of conventional type. A tension spring 116 engages the rotating star Wheel 117 of the adjusting device 115 to prevent rotation thereof after proper adjustment 4 carried in holes 119 and 120 in the brake shoe ends 112 and 113 respectively.

The supporting ends 83, 85 and 84, 36 of the brake shoe supporting member 80 can be accurately machined in a common plane whereby each of the brake shoes 90 and 100 will be carried accurately concentrically relative to the axis of the brake drum 45, and tilting of the brake shoes relative to the brake drum will be avoided during operation of the brake shoes.

The oppositely acting wheel cylinder pistons 72 engage the abutment portions 122 and 123 at the upper ends of the brake shoes 90 and 100 respectively whereby delivery of hydraulic fluid under pressure into the space of the screw 118. Opposite ends of the spring 116 are 75 124 between the pistons results in hydraulic actuation of the brake mechanism. A rubber boot-125 is provided between each of the pistons 72 and the end of the wheel cylinder 70 to eliminate dirt from entry into the wheel cylinder bore 71,

Hydraulic fluid is delivered from the pedal operated master cylinder of the motor vehicle through passages 126 and 127 provided in the axle spindle 10. The outboard end of the passage 12.7 receives a seal member 128 that is positioned in a bore 129 provided in the axle spindle 10. The seal member 128 bridges the gap across the cooperating splines or serrations in the cooperating faces of the support member 73 and the end of the wheel spindle 10 to prevent loss of brake uid in its passage to the passage 130 and the passage 131 provided in the wheel cylinder support member 73. These passages 130 and 131 conduct the hydraulic uid to the wheel cylinder bore 71 for actuation of the wheel cylinder pistons 72.

The seal member 128 is retained in place by the retaining member 132 that has the passage 130 therein.

A bleed valve 133 is provided for the wheel cylinder 70. A removable plug 134 is provided in the wheel ange 20 to gain access to the bleed valve or plug 133 for bleeding the hydraulic lines to remove air from the same.

The mechanism thu-s far described constitutes the hydraulic brake mechanism that is operated in response to operation of the brake pedal of the motor vehicle, the brakes operating in conventional manner.

Auxiliary to the hydraulic brake mechanism there is provided a mechanical brake actuating mechanism that also operates the brake shoes 90 and 100.

This mechanical brake actuating mechanism includes an actuating shaft that extends through the axial opening 14 in the axle spindle 10, the shaft 140 being journaled in the bearings 141 and 142 provided in opposite ends of the axial bore 14.

The actuating'shaft 140 has the in-board end 143 splined to receive an actuating arm 144 that is secured on the end of the shaft 140 by a pin 145 extending radially through the arm 144 and the shaft 140. An O ring seal 146 prevents entry of foreign matter between the shaft 140 and its bearing journal 142.

The actuating arm 144 has the free end thereof connected with a exible operating cable 150 that has a connector 151 pivotly secured to the free end of the arm 144 byV a pivot connection 152.l A flexible rubber boot 153 surrounds the open end of the cable 150 and extends between the connector 151 and the end 154 of a cable sheath 155 that is fastened to a bracket 156 carried on the kingpin journal 11.

l The opposite end of the actuating shaft 140 carries an actuating arm as connected thereto by a splined connection 161. A compression spring 162 is placed between the arm 160 and the journal bearing 141 of the shaft 140 to urge the shaft in one direction and thereby eliminate play and rattle from the shaft.

The actuating arm 160 has a link arm 163 attached thereto by a pivot pin 164. The opposite end of the link arm 163 is attached to a lever arm 165 by means of a pivot connection 16641 The rleverarin 165 is carriedI upon-the web ltlof the brake shoe'100'byrneans` of a pivot 'pin'17" The leverarm- 165A has-i an edge,groove171that'en gages an edge: slot 172'f'in an actuating'mem'ber. 175 that extends "between'the actuating'arm 165'and the web 91 of thebrakeshoe` 90; aswmoregparticularly,illustrated in Figure 5. The actuating. member 175 has the end thereof Opposite' to thetend containingthe edge slot 172 provided v\with ian-edge slot-176 that engages 'an-"edge slot l17,7 intheMvveb4 9.1,-of-the-brakefshoe 90f Acompressionispring A181).,-is--positioned `between the actuating membe'r`1175'and. the .web 91--of`A the ibrakelshoe 90 to continuously urge .theactuatin-gcmember175 intofengagement withtheuleverVarm-l andt by retainatheied'ge slot 217-2? of* theactuatingmetri-bei -17 55 in engagement withthe edge'lslot-ot the leverarrr 155'r l Theractuating-memberifl' hasl'a'y central opening 18d through which the Wheel cylinder 70 extends, as illustrated in Figure 2; Thus; thecactuating member 175 is symmetrically? arranged aro-und. therwheel cyliride'rti to prevent: anywrelative `angulan.displacement between-@the lever arm 16:5;'and the..web,9l ofthe brake shoegtiwhen the lever 165 is operated to urge the brake shoe 90 against the brake drum 45.

A felt pad 185 is carried on the member ll75 beneath the bleed plug 133 to absorb any leakage of brake uid from the Wheel cylinder 70 and thereby prevent brake fluid from dropping onto the brake mechanism and iinally finding its way to the surface between the brake linings and the brake drum. The member 175 has the upper surface thereof somewhat trough shaped to also aid in this purpose, and to give strength to the member 175 for transmission of braking effort from the lever 165 to the `brake shoe 90 when the actuating cable 15u is rendered Operative either by a hand brake operation or by a foot brake operation.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted as may come within the scope of the claims which follow.

What is claimed is as follows:

.1. In a motor vehicle brake mechanism, the combination of, a non-rotatable axle, a wheel rotatably supported on said axle, a brake drum carried on said wheel coaxial thereof, a brake shoe and cylinder support member having a hydraulic actuating cylinder with brake shoe actuating piston means therein and a support leg projecting substantially radially from one side of the cylmder and an anchor pin carrying boss projecting substantially radially from the opposite side of the cylinder, a slot in said boss parallel with and radial of the axis of said cylinder to receive adjacent ends of brake shoes,

. an anchor pin in said boss projecting through said slot,

a pair of brake shoes within said drum for frictionally engaging said drum each having a substantially radially disposed-web with each of adjacent ends of the webs of the shoes at one end thereof in said slot and engaging said anchor pin the portion thereof in said slot and provided with retraction spring means to effect operative connection between the said shoes and said pin and having opposite adjacent ends engaging an adjusting device, a shoe support member on said shoeV and cylinder support member substantially in the plane of said leg and pro jecting from each side of the leg at substantially a right angle thereto forming thereby a substantially T-shaped structure and provided with shoe supporting legs at each end of said guide member extending axially of said axle and having their ends in a common plane extending substantially through the plane of the outboard vertical side of said slot in said boss and engaged by the webs of said shoes to dispose said webs in said common plane normal to said axle and maintain the said shoes posi- -tioned to frictionally engage said drum, and spring urged link means between said cooperating shoe supporting legs v at each end of said shoe` support member-,1 with-the.linlc meansr extending between said s'he support member and' the shoe web engaged by the saidishoe supportingle'gsto. retain the shoe webs in engagement'withthe'saidlshoe supporting legs to maintain.l the aforesaid'structural'aligne ment. A

2. In a motorvehicle lwheel and? brake.' mechanism, combinationlof, a non-rotatable` axle, ta ,wheelzr'otatably' wheel coaxial thereof"andforming` therewitlifabrake chamber, said axle terminatinggwithini` saiddrumaand having a mounting face on-,theterminus endlth'ereof,fa brake shoe support legjsecuredg'onsaid-fmountinggface and projecting., substantially radially from saidaxl'e, .said leg includingV integrally;` therewith an'. 'hydraulic actuating cylinder intermediate -theends .offthe-,Vlegwthe .saidlleg including an anchor-pin Vcarrying-boss-projectingsu1h stantially radially fromrthevcylinder onthe-.diametricall'y opposite side :of the i cylinder-from rtli'e@pr-, ojectiori` .of the support 'leg therefrom, afslotr inNv saidfbossmarallel with and radialof thef'axis `of said,cylindentoreceivethe webs of adjacent ends -o- Sbrake' shoesasan manchon pint `in said boss and projecting transversely.- through said-slot, a pair of brake shoes within said drum for frictionally engaging said drum, said shoes having radial Webs and the adjacent ends of said webs at one end thereof engaging said anchor pin within said sloth and provided with restraction spring means to effect connection between the said shoes and said pin and having the opposite adjacent ends engaging an adjusting device, a shoe guide member on said support leg substantially in the plane of said leg and projecting from each side of the leg at substantially a right angle thereto whereby to form with said leg a generally T-shaped structure with said anchor pin disposed at the end ofthe stem of the T-shaped structure, the projecting portions of said shoe guide member having surfaces at their extremities engaged by the Webs of the shoes and disposed in a common plane that extends through the outboard side of said slot whereby to maintain the outboard side of the webs of the shoes in said common plane normal to the axis of said axle, said axle having a bore extending through the same axially therof, a rotatable shaft journaled within said bore of said axle and having opposite ends thereof projecting from opposite ends of said axle, actuating mean connected with said shaft on the external side of the wheel to effect rotation of the same, lever means pivotally mounted on one of said shoes, a brake shoe actuating member. extending 4between said lever means and the other of said shoes substantially normal to the radial position of said support leg with said support leg extending through said actuating member with the actuating member disposed equally on opposite sides of said support leg, and link means between said lever and the opposite end of said shaft for actuation of said lever and thus said shoes thereby upon rotation of said shaft.

3. In a motor vehicle wheel and brake mechanism, the combination of, a non-rotatable axle, a wheel rotatably supported on said axle, a brake drum carried on said wheel 'coaxial thereof and forming therewith a brake chamber, said axle terminating within said drum and having a mounting face on the terminus end thereof, a brake shoe support leg secured on said mounting face and projecting substantially radially from said axle, said leg including integrally therewith an hydraulic actuating cylinder intermediate the ends of the leg, the said leg including an anchor pin carrying boss projecting substantially radially from the cylinder on the diametrically opposite side of the cylinder from the projection of the support leg therefrom, a slot in said boss parallel with and radial of the axis of said cylinder to receive the webs of adjacent ends of brake shoes, an anchor pin in said boss and projecting transversely through said slot, a pair of brake shoes within said drum for operatively engaging said drum, said shoes having radial webs and the adjacent ends of said webs at one end thereof engaging said anchor pin within said slot and provided with retraction spring means to effect connection between the said shoes and said pin and having the opposite adjacent ends engaging an adjusting device, and a shoe guide member on said support leg substantially in the plane of said leg and projecting from each side of the leg at substantially a right angle thereto whereby to form with said leg a generally T-shaped structure with said anchor pin disposed at the end of the stem of the T-shaped structure, the projecting portions of said shoe guide member having surfaces at their extremities engaged by the webs of the `shoes and disposed in a common plane that extends through the outboard side of said slot whereby to maintain the outboard side of the webs of the shoes in said common plane normal to the axis of said axle, an actuating member placed around said hydraulic cylinder having one end connecting the cooperating end of said brake shoe web, a pivoting lever pivoted on the other cooperating adjacent shoe end and having a slot for receiving the opposite end of said actuating member, said pivoting lever extending downward within the brake drum, an operating lever mounted partially within said axle and extending Within said brake drum, a connecting link be.

tween said operating lever and said pivoting lever, said operating lever extending inboard of said axle and adapted for connection with an operating means.

References Cited in the iile of this patent UNITED STATES PATENTS 

